The Complete Aristotle (eng.)

points, he does grant points of that kind. It is,
then, clear that adverse criticism is not to be passed in a like
manner upon questioners and upon their arguments.
    In itself an argument is liable to five kinds of adverse
criticism:
    (1) The first is when neither the proposed conclusion nor indeed
any conclusion at all is drawn from the questions asked, and when
most, if not all, of the premisses on which the conclusion rests
are false or generally rejected, when, moreover, neither any
withdrawals nor additions nor both together can bring the
conclusions about.
    (2) The second is, supposing the reasoning, though constructed
from the premisses, and in the manner, described above, were to be
irrelevant to the original position.
    (3) The third is, supposing certain additions would bring an
inference about but yet these additions were to be weaker than
those that were put as questions and less generally held than the
conclusion.
    (4) Again, supposing certain withdrawals could effect the same:
for sometimes people secure more premisses than are necessary, so
that it is not through them that the inference comes about.
    (5) Moreover, suppose the premisses be less generally held and
less credible than the conclusion, or if, though true, they require
more trouble to prove than the proposed view.
    One must not claim that the reasoning to a proposed view shall
in every case equally be a view generally accepted and convincing:
for it is a direct result of the nature of things that some
subjects of inquiry shall be easier and some harder, so that if a
man brings people to accept his point from opinions that are as
generally received as the case admits, he has argued his case
correctly. Clearly, then, not even the argument itself is open to
the same adverse criticism when taken in relation to the proposed
conclusion and when taken by itself. For there is nothing to
prevent the argument being open to reproach in itself, and yet
commendable in relation to the proposed conclusion, or again, vice
versa, being commendable in itself, and yet open to reproach in
relation to the proposed conclusion, whenever there are many
propositions both generally held and also true whereby it could
easily be proved. It is possible also that an argument, even though
brought to a conclusion, may sometimes be worse than one which is
not so concluded, whenever the premisses of the former are silly,
while its conclusion is not so; whereas the latter, though
requiring certain additions, requires only such as are generally
held and true, and moreover does not rest as an argument on these
additions. With those which bring about a true conclusion by means
of false premisses, it is not fair to find fault: for a false
conclusion must of necessity always be reached from a false
premiss, but a true conclusion may sometimes be drawn even from
false premisses; as is clear from the Analytics.
    Whenever by the argument stated something is demonstrated, but
that something is other than what is wanted and has no bearing
whatever on the conclusion, then no inference as to the latter can
be drawn from it: and if there appears to be, it will be a sophism,
not a proof. A philosopheme is a demonstrative inference: an
epichireme is a dialectical inference: a sophism is a contentious
inference: an aporeme is an inference that reasons dialectically to
a contradiction.
    If something were to be shown from premisses, both of which are
views generally accepted, but not accepted with like conviction, it
may very well be that the conclusion shown is something held more
strongly than either. If, on the other hand, general opinion be for
the one and neither for nor against the other, or if it be for the
one and against the other, then, if the pro and con be alike in the
case of the premisses, they will be alike for the conclusion also:
if, on the other hand, the one preponderates, the conclusion too
will follow suit.
    It is also a fault in reasoning when a man shows something
through a long chain of steps, when he might employ fewer steps and
those already included in his argument: suppose him to be showing
(e.g.) that one opinion is more properly so called than another,
and suppose him to make his postulates as follows: ‘x-in-itself is
more fully x than anything else’: ‘there genuinely exists an object
of opinion in itself’: therefore ‘the object-of-opinion-in-itself
is more fully an object of opinion than the particular objects of
opinion’. Now ‘a relative term is more